Productivity and Content of Pharmaceutical Indices of Sedum aizoon l. At Different Ratios of N, P, K-Juniper Publishers

Journal of Agriculture Research- Juniper Publishers

In the experiments of mineral nutrition optimization of valuable herb Sedium aizoon L. grown in open air hydroponic conditions it was revealed the significant influence of N, P, K ratio in nutrient solution on productivity and content of physiological-biochemical, pharmaceutical indices of plant. Moreover, the optimum ratio of N, P, K was 10:40:50 atom% for the output of medicinal raw material, and in the roots it was 16:23:61; 17:22:61; 15:25:60; 21:21:58; 15:43:42 և 26:18:56 atom% for biologically active compounds saponins, arbutin, β-sitosterol, olienic acid, tannins and еxtractives, accordingly.

Keywords: Nutrition optimalization; Hydroponics; Sedium aizoon L., Physiological-pharmacological indices; Productivity

Introduction

Medicinal herb Sedum aizoon L. have been introduced to soilless culture taking into consideration the unique properties and high demand of stimulating and adaptive plant species. Long-term researches approved high productivity and possibility of hydroponic cultivation of Sedum aizoon L. and revealed its agro-radiochemical, physiological–biochemical characteristics in conditions of hydroponics and soil culture [1-4]. At the same time, in the Institute of Hydroponics Problems of NAS RA scientific experiments were done for optimization of the mineral nutrition of some medicinal, essential oil bearing, dye-bearing crops, also mathematical models of plant productivity increase have been received, and the influence of N, P, K ratio of the nutrient solution on productivity of plants and on stimulation of bioactive compounds’ biosynthesis has been confirmed [5-8].

The aim of research was to study the influence of N, P, K different ratios on the plant productivity taking account above mentioned and medicinal specificities and prospects of Sedum aizoon L.

Materials and Methods

Sedum aizoon L. is a perennial herb with 25-45cm height that belongs to the Grassulaceae family. The root and over ground parts of the plant are used for medical purposes. In the roots of plant there were found carbohydrates, oleic acid, β-sitosterol, phenols and their derivatives (arbutin), tannins, triterpenoid saponins that have stimulating properties. In the leaves of plant there were found vitamin C, carotenoids, tannins and negligible amounts of arbutin and saponins. The plant is used for treatment of pneumo nia, hepatitis, kidney dieseases and other diseases. It has also abilities to reduce temperature, heal wounds and raise vitality [9-11].

The experiments were done with the 8 repeats in hydroponic vegetative vessels with 0.16m2 surface, where the mixture of volcanic slag and gravel with 1:1 ratio was used as a substrate. Plants were nourished two times during a day with the Davtyan’s 1N nutrient solution [12] with the following three proportions of N, P, K: N70P15K15, N15P70K15 and N15P15K70 atom %. The methods of Homes’s Systematic variations [13] and Vakhmistrov’s “correlation probing” [14] were used to clarify the optimal ratio of N, P, K, and to count correlation coefficient between plant productivity and N, P, K ratio in nutrient solution. Physiological-biochemical and medicinal analyses of experimental plants were done during vegetation: water-holding forces, the sap osmotic pressure in the leaves were measured according Gusev [15], the content of photosynthetic pigments was estimated according Wettstein [16], the content of vitamin C was determined according Yermakov [17] and the content of tannins, extractive compounds and humidity in the dry medicinal raw material was defined according SPh XI [18]. The amount of saponins, arbutin, β-sytosterin, oleic acid in the roots was determined by the method of preparative thin layer chromatography. The samples of “Sigma Aldrich” firm were used as standards.

Results and Discussion

The experiment results for optimization of Sedum aizoon L. mineral nutrition is shown in the Tables 1-4. It was found that high amount of potassium in the nutrient solution promotes the increase of plant productivity and improvement of some medicinal indices (Table 1,2).

The content of bioactive substances in the variant with highest content of K exceeded the variant with highest content of N, in average, 1.6-2.3 times and the variant with highest content of P 1.7-1.8 times. The high amount of nitrogen in nutrient solution had a negative influence on tannins content in the roots and accumulation of dry medicinal raw material.

N, P, K effective ratios were calculated theoretically for dry medicinal raw material of Sedum aizoon L. using the method of “systematic variations” of Homes: 10:40: 50 atom % for output of over ground mass and total medicinal raw material and 11:40:49 atom % for roots. Also, correlation coefficients between the plant productivity and N:P:K ratio in the nutrient solution was defined that were-0.998; -0.999 and -0.997, respectively.

Mathematical models of plant productivity enhancement were developed in form of regression equations (for over ground mass: y=19.82-0.27x; for roots: y=11.79-0.157x; for total medicinal raw material: y=30.17-0.383x). The analyses of equations allow to suppose that it is possible to receive maximum harvest of Sedum aizoon L. at nutrient solution with optimal N:P:K ratio: for over ground mass it equals to 19.82g/plant, for roots it is 11.79 g/ plant, for total medicinal raw material it makes up 30.17g/plant and the 1 atom % shift from above mentioned values will bring to the decrease of yield on 0.270g/plant; 0.157g/plant; 0.383g/plant amount, respectively.

Similar calculations were done also for the definition of bioactive compounds (saponins, arbutin, β-sitosterol, oleic acid, tannins and extractive substances) content in the roots of Sedum aizoon L. (Table 3).

Mathematical models of plant productivity enhancement were brought out in form of regression equations for the content of:

a. Saponins: y=1.74-0.0185x.

b. Arbutin: y=0.77-0.0081x.

c. β-sitosterol: y=0.1-0.0011x.

d. Oleic acid: y=0.057-0.00054x.

e. Tannins: y=8.7-0.0983x.

f. Extractive substances: y=22.84-0.223x.

These equations prove, that in optimal conditions of nutrient solution it is possible to receive maximum amount of saponins, arbutin, β-sitosterol, oleic acid, tannins and extractive substances in the roots of Sedum aizoon L.

Thus, relatively high accumulation of water’s more mobile fraction, chlorophyll (a+b) and vitamin C was observed in case of nitrogen and phosphorus high portions in nutrient solution, and an increase of sap osmotic pressure and osmotic bound water was recorded in variants with predominance of phosphorus and potassium. Relatively high portion of phosphorus in nutrient solution provided the increase of carotenoids content in the leaves (Figure).

Conclusion

The ratio of N, P, K in Davtyan’s 1N nutrient solution sufficiently influences on the productivity and bioactive substances content of Sedum aizoon L. Whereupon, effective ratios of N, P, K are 10:40:50 atom% in the case of total medicinal raw material output, and are 16:23:61; 17:22:61; 15:25:60; 21:21:58; 15:43:42 and 26:18:56 atom % in the roots in the case of bioactive compounds saponins, arbutin, β-sitosterol, oleic acid, tannins and extractive substances, respectively.

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